A BBC doctor has issued a warning to the millions of people in the UK taking antidepressants, following new research that highlights significant side effects such as weight gain, weight loss, and changes in heart rate and blood pressure. Dr Kasim Ahmed spoke on BBC Morning Live about the findings, which analysed data from over 50,000 patients across 150 studies.
The research, led by academics from King's College London, examined the effects of 30 antidepressants compared to a placebo over the first eight to twelve weeks of treatment. It found that some drugs, such as amitriptyline and nortriptyline, can cause weight gain of up to 2kg, while others like sertraline and citalopram may lead to weight loss of about 1kg.
Dr Ahmed emphasised that these medications are prescribed for a reason, typically for mood disorders like depression or anxiety, and are effective at managing symptoms. However, he highlighted that the side effects are not universal and affect only some patients. The study also noted that amitriptyline and nortriptyline can increase heart rate by up to nine beats per minute and raise blood pressure by around 10 points, whereas sertraline and fluoxetine may lower heart rate and blood pressure.
In England, nearly 93 million antidepressant prescriptions were issued in 2024/25 to about 8.89 million patients. Sertraline was the most prescribed, given to 2.9 million patients, while amitriptyline was prescribed to 2.2 million. Dr Ahmed advised anyone experiencing side effects to consult their doctor before making any changes to their medication.
